Electronics enclosure with solar shield

ABSTRACT

An apparatus for shielding an electronics enclosure is disclosed. The apparatus includes an inner enclosure that houses electronic components. An outer enclosure surrounds the inner enclosure, and is separated from the inner enclosure by a gap. The outer enclosure preferably comprises plastic, and comprises a plurality of perforations uniformly distributed over its surface. The plurality of perforations allow air to flow into the gap between the outer enclosure and the inner enclosure. At the same time, the perforations are configured and dimensioned such that they substantially prevent sunlight from directly striking the surface of the inner enclosure. In this manner, the apparatus prevents overheating of the electronic components while minimizing the space taken up by the enclosure.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention claims priority to Provisional Patent ApplicationSer. No. 60/749,577, filed Dec. 13, 2005, the entirety of which isincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to enclosures for electronic equipment.More specifically, the present invention relates to an enclosure forelectronic equipment that effectively dissipates the internallygenerated heat of the electronic equipment.

BACKGROUND OF THE INVENTION

Over the past 50 years, electronic equipment has become more and moreprevalent in the average person's everyday life. With the invention ofthe transistor, electronics have rapidly become more and more powerfuland sophisticated. At the same time, advances in technology have allowedelectronics to penetrate nearly every aspect of our everyday lives. Thehome is no exception.

Increasingly, electronic equipment has allowed us to communicate withone another, or to receive other types of media services such astelevision, telephone service, internet, and satellite service. Toprovide these services, media providers often run cables of varyingtypes from remote locations to individual homes. The cables, of varyingtypes, allow individuals to receive telephone, internet, and cableservice.

Each individual home or unit has an interface, referred to as a NetworkInterface Device (NID), located outside that allows a home's internalwiring to communicate with the cables from the media providers. Theinterface typically includes electronic equipment and circuitry. Thenature of electrical circuitry requires that it be protected from theoutside environment in order to function properly. As such, differentenclosures have been devised in order to protect this equipment from theelements, such as wind, water, dust, and heat.

Overheating of equipment due to solar radiation, and heat generated bythe electrical equipment itself, is the source of significant problems.Electrical equipment that overheats can malfunction, which results incostly repairs. To avoid overheating, enclosures employ a wide varietyof techniques in an attempt to maintain an ambient temperature within anenclosure. This problem is not as prevalent with indoor electricalenclosures, which are currently more widespread, because theseenclosures do not need to be sealed and are not exposed to solarradiation.

Although the outdoor Network Interface Device (NID), the housing for thedemarcation point, is a mature technology, the inclusion ofheat-dissipating and environmentally sensitive electronics andopto-electronics in particular in outdoor NID-like applications is arelatively new application. Previous outdoor applications have addressedthe cooling problem by packaging the electronics in an enclosure that islarger in surface area, and hence less desirable by the customer, thanis otherwise necessary for the physical packaging of the electronics andassociated hardware. Prior art enclosures have also been designed tolimit air intake to the bottom surface of an enclosure, and air exhaustto the top of the enclosure.

A drawback of more compact enclosures currently available is that theyresult in operating conditions for the electronic devices that arehotter than desirable under worst case environmental conditions and willreduce the life and reliability of the system below desirable levels.Higher power applications typically employ expensive and power-hungrycooling fans.

A continuing need exists for a low cost electrical enclosure that iscapable of efficiently cooling electronic equipment. Moreover, acontinuing need also exists for an electrical enclosure that can shieldsensitive electronic equipment from solar radiation.

SUMMARY OF THE INVENTION

The present invention comprises a method and apparatus for mounting andcooling electronic equipment in a low-cost, preferably plastic,environmentally protected enclosure that is protected from excessivesolar heating by a ventilated shield. The solar shield intercepts thesolar radiation and allows the ambient environment on its outsidesurfaces and near ambient conditions on its inside surface. The surfacetemperature of the environmentally protected enclosure is reducedsignificantly relative to an enclosure without a solar shield. Theinvention takes advantage of the fact that the surfaces of the sealedelectronics enclosure are not exposed to solar radiation and yet, withadequate ventilation of the solar shield, can be exposed to cooling airnear the outdoor ambient temperature. The ventilation openings in thesolar shield, though they may admit rain and dust along with coolingair, are sized to exclude bees and wasps which are particularlytroublesome in outdoor enclosures.

According to one aspect, the present invention comprises an apparatusfor enclosing electronics. The apparatus includes an outer enclosurehaving a plurality of perforations substantially uniformly distributedabout its surface, and an inner enclosure positioned within the outerenclosure. Preferably, the inner enclosure has one or more electroniccomponents selectively positioned inside. It is desirable for the outerenclosure to be configured and dimensioned to be spaced from the innerenclosure.

According to this embodiment, each of the plurality of perforationssubstantially prevent sunlight from directly striking an outer surfaceof the inner enclosure. At the same time, each of the plurality ofperforations allow air to pass to the space between the inner and outerenclosure. The perforations are configured and dimensioned such thatabout 95% or more of the sunlight that strikes each of the plurality ofperforations from an angle of about 45 degrees or more relative tonormal are substantially prevented from striking the surface of theinner enclosure.

In one embodiment the outer enclosure preferably comprises plastic thathas a thickness of between about 2.5 mm and about 3.5 mm. The width ofthe perforations may be between about 5.5 mm and about 6.5 mm. Finally,the height of the perforations is preferably between about 2.5 mm andabout 3.5 mm.

According to another embodiment, the present invention comprises anapparatus for enclosing electronic components. The apparatus includes afirst housing having one or more electronic components selectivelypositioned therein, and a second housing configured and dimensioned toenclose the first housing. It is desirable for the second housing toinclude a plurality of perforations that substantially prevent sunlightfrom directly striking the first housing. The second housing ispreferably spaced from the first housing by a distance of between about10 mm and about 14 mm. Preferably, the height of the perforations isbetween about 2 mm and about 4 mm, and the width of the perforations isbetween about 4 mm and about 8 mm.

According to yet another embodiment, the present invention comprises anapparatus for enclosing electronic devices. The apparatus includes aninner enclosure having one or more electronic devices positioned inside,and an outer enclosure configured and dimensioned to surround the innerenclosure. The inner enclosure is preferably separated from the outerenclosure by a gap that is between about 8 mm and about 16 mm. The outerenclosure comprises a plurality of perforations, each of which allow airto enter the gap.

According to this embodiment, the outer enclosure comprises plastic, andthe plurality of perforations are uniformly distributed on the surfaceof the outer enclosure. The plurality of perforations substantiallyprevent sunlight from directly striking a surface of the innerenclosure. For instance, between about 80% and about 100% of thesunlight that strikes the outer enclosure from an angle of about 45° ormore relative to normal is prevented from directly striking the surfaceof the inner enclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention can be ascertained fromthe following detailed description that is provided in connection withthe drawings described below:

FIG. 1 shows an exemplary embodiment of the present invention;

FIG. 2 shows a side view of one embodiment of the present invention; and

FIG. 3 shows a cross-section of a ventilation hole according to oneaspect of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Manufacturers of electrical enclosures prefer to produce the enclosuresin high volume in order to reduce their cost. This requirement tends tofavor a molded plastic enclosure cooled by natural convection, althoughsuch a design does not dissipate the internally generated heat of theelectronics effectively enough for a compact design with long life. Thehousing of electronic equipment on the exterior of a residence forapplications such as fiber to the premises introduces a cooling problemdue to the following requirements: (i) compact packaging; (ii) sealingagainst contamination; (iii) additional thermal loading from solarradiation; (iv) low cost due to widespread deployment; and (v) lowmaximum device temperatures for maximum life and reliability.Temperature rise due to solar heating is particularly problematic insealed enclosures. In enclosures that hold electronics that have a lowoperating power, temperature rise due to solar loading can far exceedtemperature rise due to self-heating of the electronics.

To overcome this and other disadvantages, the present invention providesan electronics enclosure that comprises a solar shield. Generally, theenclosure comprises an inner enclosure that isolates the electronicsfrom the outside environment. The inner enclosure, in turn, issurrounded by an outer enclosure that includes perforations over atleast a portion of its surface area. The perforations are configured anddimensioned such that air is capable of passing into a space between theinner and outer enclosures. The flow of air around the inner enclosureallows heat to be dissipated, cooling the electronics positioned withinit. At the same time, the perforations are configured and dimensionedsuch that the inner enclosure is shielded from solar radiation.Preferably, the perforations prevent the entry of insects, such as beesand wasps, into the space between the inner enclosure and the outerenclosure.

The enclosure may house any type of equipment. Preferably, electronicequipment is housed within the enclosure. However, it is contemplatedthat other non-electronic hardware may also be enclosed. Thenon-electronic equipment may comprise materials that support orotherwise interact with the electronic equipment. The present inventionmay be used in combination with other elements, e.g., heat sinks. Anexample of a heat sink that may be used is disclosed in a co-pendingU.S. Application filed on Dec. 13, 2006, entitled “Heat Sinks forElectronic Enclosures,” Attorney Docket No. 19546.0005, the entirety ofwhich is incorporated herein by reference.

In one embodiment, the inner and outer enclosures comprise the samematerial. In other embodiments, however, the inner and outer enclosuresmay comprise different materials. It is desirable for the enclosures tocomprise a material that reduces cost and is lightweight. As such, theenclosures are preferably comprised of a plastic. However, theenclosures, or portions thereof, may comprise a variety of materialsother than plastic. These materials may include, for example, metal,alloys, wood, glass, composites, fiberglass, and the like.

Each enclosure may have any desired dimensions, as will be appreciatedby those skilled in the art. In other words, the height, width, anddepth of each enclosure may be chosen according to a particularapplication. Factors that may be considered include, but are not limitedto, the type of electronic equipment enclosed, the dimensions of theelectronic equipment and/or hardware enclosed, the space availableoutside a residence, and the like.

FIG. 1 is a diagram showing one exemplary embodiment of the presentinvention. FIG. 1 shows the enclosure of the present invention in anunassembled position in order to facilitate the explanation of thisembodiment of the present invention. It is desirable for the outerenclosure to include two parts, e.g., a solar shield 10 and a mountingbracket 12. Similarly, the inner enclosure includes a first portion 14and a second portion 16.

The solar shield 10 and the mounting bracket 12 may comprise any desireddimensions. Preferably, however, the dimensions of the two parts 10, 12are selected such that they are able to enclose the inner enclosure. Anexample of this is shown in FIG. 2, which is a side view of the FIG. 1embodiment in the assembled position. Similarly, the dimensions of thefirst portion 14 and the second portion 16 of the inner enclosure may beselected such that the electronics and/or other non-electronic hardwaremay be fully enclosed.

In one embodiment, the outer enclosure of the present invention ismounted to the wall, or another portion, of a residence. As such, themounting bracket 12 preferably includes one or more mounting feet thatenable the mounting bracket 12 to rest flush against the surface of thewall of the residence. Optionally, the mounting bracket 12 may include afastener, e.g., a screw, bolt, and the like, that passes from the insideof the mounting bracket 12, through the back wall of the bracket 12(facing the wall), in order to fasten the mounting bracket 12 to thesurface of the wall. Skilled artisans will recognize that otherfastening mechanisms may be employed as desired. For instance, thefasteners may pass through the mounting feet 18, or alternately thesurface of the mounting feet 18 that contacts the wall may include anadhesive. In other embodiments, combinations of these and otherfastening mechanisms known to those skilled in the art may be used.

The solar shield 10 and the mounting bracket 12 may be connected in anydesirable manner, using an fastening mechanism known to those skilled inthe art. Preferably, the solar shield 10 and the mounting bracket 12 areconnected through selectively engageable parts. For example, in oneembodiment the solar shield 10 may include a protrusion, and themounting bracket 12 may include a corresponding recess. In order toconnect the solar shield 10 and the mounting bracket 12, the protrusionmay be inserted into the recess. At least a portion of the protrusionmay be configured and dimensioned such that it is slightly larger thanthe opening of the recess, such that friction forces provide resistanceagainst disengagement. Alternately, the solar shield 10 and the mountingbracket 12 may comprise a “lock and key” mechanism that prevents theirdisengagement. In still other embodiments, adhesives, Velcro, hinges, orthe like may be employed. Apparatus and methods for connecting twoportions of an enclosure are well known to skilled artisans, any ofwhich may be used, and the present invention is not intended to belimited to any particular apparatus or method of engagement.

In a manner similar to the outer enclosure, the inner enclosure may alsoemploy any of the apparatus and methods of engagement described above.In one embodiment, however, it is desirable for the inner enclosure tobe tightly sealed when it is engaged. This provides the advantage ofisolating the electrical components within the inner enclosure from anyenvironmental factors that may affects its operation, e.g., dust, wind,moisture, and the like. An example of a sealed engagement 30 isillustrated in FIG. 2. The inner enclosure, according to one embodiment,may be configured and adapted to receive wires 32, cables, and the likethat may be connected to the electronic components, as shown in FIG. 2.

The sealed engagement 30 of the inner enclosure may be formed in asimilar manner as the engagement described above. Skilled artisans willrecognize that additional materials may be necessary to form a seal,such as rubber, metal, and the like. Both the inner and outer enclosure,despite the engagement of its parts, should be capable of beingseparated to allow access to both the area between the inner and outerenclosure as well as the electrical components positioned within theinner enclosure. To facilitate the engagement of the outer enclosure andthe inner enclosure, the inner enclosure preferably includes hinges 20that are capable of engagement with the parts of the outer enclosure.

As shown in FIG. 1, solar shield 10 and the mounting bracket 12 of theouter enclosure include a plurality of ventilation holes 22, orperforations. The present invention is not intended to be limited to anynumber of ventilation holes 22. The ventilation holes 22 may beselectively positioned in any desirable manner. According to one aspect,the ventilation holes 22 may be positioned such that the air flowresults in a maximum amount of cooling of the electronic componentslocated within the inner enclosure. The ventilation holes 22 arepreferably located on both parts of the outer enclosure, i.e., the solarshield 10 and the mounting bracket 12. In other embodiments, however,the ventilation holes 22 may only be located on one part of the outerenclosure. It is desirable for the ventilation holes 22 to be uniformlylocated over the surface of the outer enclosure. One advantage ofuniformly positioning the ventilation holes 22 is that cooling may beimproved by maximizing air intake.

FIG. 3 is a diagram showing a cross-sectional view of an exemplaryventilation hole 22 of FIG. 1. The ventilation holes 22 are preferablyconfigured and dimensioned such that they are able to admit air whilepreventing the entry of larger debris and even insects, e.g., bees andwasps, that are often troublesome in outdoor enclosures. The ventilationholes 22 may comprise any desired shape known to those skilled in theart including, but not limited to, circular, oval, any polygon, or evenan irregular shape. Preferably, however, the ventilation holes 22 arerectangular. Furthermore, each of the plurality of ventilation holes 22may have the substantially same dimensions and shape, or alternately theventilation holes 22 may have substantially different dimensions andshape.

In one embodiment, the height 24 of the ventilation hole 22 may bevaried. Preferably, the height 24 of the ventilation hole 22 is betweenabout 1.5 mm and about 4.5 mm. More preferably, the height 24 of theventilation hole 22 is between about 2.5 mm and about 3.5 mm. Mostpreferably, the height 24 of the ventilation hole 22 is between about2.85 and about 3.15 mm.

In another embodiment, the height 24 of the ventilation hole 22 ispreferably about 5 mm or less. More preferably, the height 24 of theventilation hole 22 is about 4 mm or less. Most preferably, the height24 of the ventilation hole 22 is about 3 mm or less. In yet anotherembodiment, the height 24 of the ventilation hole 22 is preferably about2 mm or greater. More preferably, the height 24 of the ventilation hole22 is about 3 mm or greater. Most preferably, the height 24 of theventilation hole 22 is about 4 mm or greater.

The width 26 of the ventilation hole 22 may also be varied as desired.In one embodiment, the width 26 of the ventilation hole 22 is preferablybetween about 3 mm and about 9 mm. More preferably, the width 26 of theventilation hole 22 is between about 4 mm and about 8 mm. Mostpreferably, the width 26 of the ventilation hole 22 is between about 5mm and about 7 mm.

According to another aspect of the present invention, the width 26 ofthe ventilation hole 22 is about 12 mm or less. More preferably, thewidth 26 of the ventilation hole 22 is about 8 mm or less. Mostpreferably, the width 26 of the ventilation hole 22 is about 6 mm orless. According to still another embodiment, the width 26 of theventilation hole 22 is preferably about 3 mm or greater. Morepreferably, the width 26 of the ventilation hole 22 is about 6 mm orgreater. Most preferably, the width 26 of the ventilation hole 22 isabout 8 mm or greater.

As shown in FIG. 3, the depth 28 of the ventilation hole 22, and thusthe thickness of the outer enclosure, may also be varied as desired. Inone embodiment, the depth 28 of the ventilation hole 22 is preferablybetween about 1.5 mm and 4.5 mm. More preferably, the depth 28 of theventilation hole 22 is between about 2 mm and about 4 mm. Mostpreferably, the depth 28 of the ventilation hole 22 is between about 2.5mm and about 3.5 mm.

In another aspect of the present invention, the depth 28 of theventilation hole 22 is preferably less then about 10 mm. Morepreferably, the depth 28 of the ventilation hole 22 is less than about 6mm. Most preferably, the depth 28 of the ventilation hole 22 is lessthan about 3 mm. According to another embodiment, the depth 28 of theventilation hole 22 is preferably greater than 2 mm. More preferably,the depth 28 of the ventilation hole 22 is greater than about 3 mm. Mostpreferably, the depth 28 of the ventilation hole 22 is greater thanabout 6 mm.

To facilitate movement of air, the outer enclosure is spaced asufficient distance away from the inner enclosure, as illustrated in theFIG. 3 embodiment. At the same time, it is desirable to minimize thedistance of between the inner and outer enclosure in order to reduce theamount of space that the enclosure occupies. In one embodiment, thedistance between the outer enclosure and the inner enclosure ispreferably between about 6 mm and about 18 mm. More preferably, thedistance between the outer enclosure and the inner enclosure is betweenabout 9 mm and about 15 mm. Most preferably, the distance between theouter enclosure and the inner enclosure is between about 11 mm and about13 mm.

In another embodiment, the distance between the outer and innerenclosures is preferably about 25 mm or less. More preferably, thedistance between the outer and inner enclosures is about 20 mm or less.Most preferably, the distance between the outer and inner enclosures isabout 15 mm or less. According to other embodiments, the distancebetween the outer and inner enclosures is preferably about 8 mm orgreater. More preferably, the distance between the outer and innerenclosures is about 15 mm or greater. Most preferably, the distancebetween the outer and inner enclosures is about 25 mm or greater.

One advantage of configuring and dimensioning the ventilation holes 22in the manner described above is that sunlight can be prevented fromdirectly striking the surface of the inner enclosure, reducing theamount of heat to which the electronic components are exposed. In otherwords, the ventilation holes 22 are preferably configured anddimensioned such that they substantially minimize the amount of sunlightthat strikes the inner enclosure.

Those skilled in the art will recognize that sunlight strikes thehorizontal and vertical surfaces of the shield at angles of about 45° ormore, relative to normal, during much of the day. As illustrated in FIG.3, sunlight that strikes the ventilation holes 22 of the solar shield 10from these angles (about 45° or more relative to normal) issubstantially prevented from passing through to the inner enclosure.Preferably, about 80% or more of the sunlight that strikes the outerenclosure is prevented from directly striking the surface of the innerenclosure. More preferably, about 90% or more of the sunlight thatstrikes the outer enclosure is prevented from directly striking thesurface of the inner enclosure. Most preferably, about 95% or more ofthe sunlight that strikes the outer enclosure is prevented from directlystriking the surface of the inner enclosure.

According to another embodiment, between about 80% and about 100% of thesunlight that strikes the outer enclosure is prevented from directlystriking the surface of the inner enclosure. More preferably, betweenabout 90% and about 100% of the sunlight that strikes the outerenclosure is prevented from directly striking the surface of the innerenclosure. Most preferably, between about 99% and about 100% of thesunlight that strikes the outer enclosure is prevented from directlystriking the surface of the inner enclosure.

As shown in FIG. 2 and described above, one embodiment of the presentinvention may be mounted or otherwise attached and/or secured to theexterior of a residence, preferably a wall of the residence. In itssealed configuration, the present invention allows air to pass throughthe ventilation holes 22 of the outer enclosure. The selectivelypositioned ventilation holes 22 allow air to pass through the outerenclosure. At the same time, the ventilation holes 22 are configured anddimensioned such that most of the sunlight that strikes the outerenclosure does not directly strike the inner enclosure. Moreover, theventilation holes 22 substantially prevent the entry of insects andother objects of similar dimensions. As the air enters the space betweenthe inner and outer enclosure, heat is effectively removed by naturalconvection. One advantage of the present invention, therefore, is thatthe surface temperature of the inner enclosure is reduced significantly.

Although the present invention has been described with reference toparticular embodiments, it will be understood to those skilled in theart that the invention is capable of a variety of alternativeembodiments within the spirit of the appended claims.

1. An apparatus for enclosing electronics, comprising: an outerenclosure having a plurality of perforations substantially uniformlydistributed about its surface; and an inner enclosure positioned withinthe outer enclosure, wherein the inner enclosure has one or moreelectronic components selectively positioned inside; wherein the outerenclosure is configured and dimensioned to be spaced from the innerenclosure.
 2. The apparatus of claim 1, wherein each of the plurality ofperforations substantially prevent sunlight from directly striking anouter surface of the inner enclosure.
 3. The apparatus of claim 1,wherein each of the plurality of perforations allow air to pass to thespace between the inner and outer enclosure.
 4. The apparatus of claim1, wherein about 95% or more of the sunlight that strikes each of theplurality of perforations from an angle of about 45 degrees or more,relative to normal, are substantially prevented from striking a surfaceof the inner enclosure.
 5. The apparatus of claim 1, wherein the outerenclosure comprises plastic.
 6. The apparatus of claim 1, wherein thewidth of the perforations is between about 5.5 mm and about 6.5 mm. 7.The apparatus of claim 1, wherein the height of the perforations betweenabout 2.5 mm and about 3.5 mm.
 8. An apparatus for enclosing electroniccomponents, comprising: a first housing having one or more electroniccomponents selectively positioned therein; and a second housingconfigured and dimensioned to enclose the first housing; wherein thesecond housing includes a plurality of perforations that substantiallyprevent sunlight from directly striking the first housing.
 9. Theapparatus of claim 8, wherein the plurality of perforations areuniformly distributed about the surface of the second housing.
 10. Theapparatus of claim 8, wherein the second housing comprises plastic. 11.The apparatus of claim 8, wherein the thickness of the second housing isbetween about 2.5 mm and about 3.5 mm.
 12. The apparatus of claim 8,wherein the second housing is spaced from the first housing.
 13. Theapparatus of claim 12, wherein the space between the second housing andthe first housing is between about 10 mm and about 14 mm.
 14. Theapparatus of claim 8, wherein: the height of the perforations is betweenabout 2 mm and about 4 mm; and the width of the perforations is betweenabout 4 mm and about 8 mm.
 15. An apparatus for enclosing electronicdevices, comprising: an inner enclosure having one or more electronicdevices positioned inside; and an outer enclosure configured anddimensioned to surround the inner enclosure; wherein the inner enclosureis separated from the outer enclosure by a gap; and wherein the outerenclosure comprises a plurality of perforations, wherein each of theplurality of perforations allow air to enter the gap.
 16. The apparatusof claim 15, wherein the outer enclosure comprises plastic.
 17. Theapparatus of claim 15, wherein the plurality of perforations areuniformly distributed on the surface of the outer enclosure.
 18. Theapparatus of claim 15, wherein the plurality of perforationssubstantially prevent sunlight from directly striking a surface of theinner enclosure.
 19. The apparatus of claim 15, wherein between about80% and about 100% of the sunlight that strikes the outer enclosure froman angle of about 45° or more relative to normal is prevented fromdirectly striking a surface of the inner enclosure.
 20. The apparatus ofclaim 15, wherein the gap is between about 8 mm and about 16 mm.